Analysis of Coil Misalignment in MCRWPT System

Coil misalignment often takes place in wireless power transfer (WPT) systems. It may result in decrease of transfer efficiency and system instability. In this paper the mutual inductance model and the circuit equation of Magnetic Coupling Resonant WPT (MCRWPT) are established firstly. And the influence of the mutual inductance on the transfer characteristic parameters is analyzed. Then the transfer power and efficiency under three transfer modes with different sizes between two coils in the offset state are studied. Based on the analysis results, a method to improve the transfer efficiency of the MCRWPT system is proposed. Finally, the analysis results and the feasibility of the proposed method are verified, through the simulations and experiments.